1. Field of the Invention
This invention relates to a multilayered integral chemical analysis element for the blood, and, in particular, to an element which permits the assay of whole blood.
2. Description of the Prior Art
Blood samples for use in analyzing chemical components of the blood, e.g., glucose, albumin, calcium, urea, uric acid, bilirubin, glycerol, cholesterol, cho lesterol ester, etc., include whole blood and the fluid part of blood left after performing a troublesome operation of removing the formed components, i.e., the plasma or serum. Needless to say, the use of whole blood permits simple and rapid determination of the chemical components of blood and is especially desirable for analyzing the blood in the case of an emergency.
Due to technical difficulties, a dry-method of chemically analyzing blood simply and rapidly using whole blood as a sample and an analytical material therefor have not yet been provided. For a simple and rapid dry assay of blood, inventions in which a multilayered integral chemical analysis element comprising a water-impermeable and light-permeable (transparent) support, a reagent layer and a porous spreading layer laminated in this order, and a multilayered integral chemical analysis element of the same structure as above except that a filter layer is formed on the porous spreading layer have been described, for example, Japanese Patent Applications (OPI) Nos. 11395/74 (U.S. Pat. No. 3,663,374), 53888/74 (U.S. Pat. No. 3,992,158), 137192/75 (U.S. Pat. No. 3,983,005), 40191/76 (U.S. Pat. No. 4,042,335), 3488/77 (U.S. Pat. No. 4,066,403), 131786/77 (U.S. Pat. No. 4,050,898), 142584/77 (U.S. Pat. No. 4,053,381) and 24893/78 (U.S. patent application Ser. No. 715,796, filed Aug. 19, 1976), abandoned, and U.S. Pat. Nos. 3,992,158 and 3,526,480. (The term "OPI" as used herein refers to a "published unexamined Japanese patent application".) These analysis elements are used in an assay in which the blood serum is used as an assay sample. The procedure itself is simple, but the serum must be separated from the whole blood and this is a troublesome operation which cannot be omitted. Thus, these conventional elements, and assays do not meet emergency needs.
Japanese Patent Application (OPI) No. 11395/74 (U.S. Pat. No. 3,663,374) discloses a method of determining the oxygen in the blood using whole blood as a sample by removing formed components using a sheet-like filter. Such a method, however, is not suited for general application, because the material, device and the method of operation used are special.
The term "formed components" as used herein means leucocytes (granulocyte, lymphocyte and monocyte), earthrocytes and platelets.